DTW -> NRT = 13:25
Not as massive as some on here but my longest:
NW/CO SDF->DTW->NRT->GUM Total travel time to GUM (incl. layovers) = 23:25
Return = 28:01 (longer layovers)
Longest segment = DTW-NRT 13:25 (listed flight time - actual time on board, add 1:00 for boarding, taxi, & deplane)
TG for WBC/WC